Prospective, randomized, double-blind study of safety and tolerability of intravesical resiniferatoxin (RTX) in interstitial cystitis (IC)

Mechanotransduction in the urothelium: ATP signalling and mechanoreceptors

The urothelium, which covers the inner surface of the bladder, is continuously exposed to a complex physical environment where it is stimulated by, and responds to, a wide range of mechanical cues. Mechanically activated ion channels endow the urothelium with functioning in the conversion of mechanical stimuli into biochemical events that influence the surface of the urothelium itself as well as suburothelial tissues, including afferent nerve fibres, interstitial cells of Cajal and detrusor smooth muscle cells, to ensure normal urinary function during the cycle of filling and voiding. However, under prolonged and abnormal loading conditions, the urothelial sensory system can become maladaptive, leading to the development of bladder dysfunction. In this review, we summarize developments in the understanding of urothelial mechanotransduction from two perspectives: first, with regard to the functions of urothelial mechanotransduction, particularly stretch-mediated ATP signalling and the regulation of urothelial surface area; and secondly, with regard to the mechanoreceptors present in the urothelium, primarily transient receptor potential channels and mechanosensitive Piezo channels, and the potential pathophysiological role of these channels in the bladder. A more thorough understanding of urothelial mechanotransduction function may inspire the development of new therapeutic strategies for lower urinary tract diseases.

Safety and efficacy of intravesical instillation of resiniferatoxin in healthy cats: A preliminary study

Objectives

To evaluate the safety of intravesical application of resiniferatoxin (RTX) in healthy cats and its effects on calcitonin gene-related peptide (CGRP) and substance P (SP) produced by C-fibers.

Methods

Seven adult female cats received either 25 mL of saline (control; n = 1), or intravesical RTX at 5, 25, or 50 μg in 25 mL of saline to a final concentration of 0.2 μg/mL (318 nM), 1 μg/mL (1,591 nM), and 2 μg/mL (3,181 nM) (n = 2 per group). The treatment was instilled into the urinary bladder for 20 min. Plasma concentrations of RTX were measured at 0, 0.5, 1, and 4 h. Physical exam, complete blood count, and serum biochemical analysis were performed on day 0, 7, and 14. After 14 days, the sacral dorsal root ganglia (DRG) and the urinary bladder were harvested for histological and immunofluorescence analysis.

Results

Intravesical RTX was well tolerated and plasma concentrations were below the quantifiable limits except for one cat receiving 1 μg/mL. Mild to moderate histopathological changes, including epithelial changes, edema, and blood vessel proliferation, were observed at lower doses (0.2 and 1 μg/mL), and were more severe at the higher dose (2 μg/mL). C-fiber ablation was observed in the urinary bladder tissue at all doses, as shown by an apparent reduction of both CGRP and SP immunoreactive axons.

Conclusion

A dose of 25 μg (1 μg/mL) of RTX instilled in the urinary bladder of healthy cats appeared to decrease the density of SP and CGRP nerve axons innervating bladder and induced moderate changes in the bladder tissue.

Acute Intravesical Capsaicin for the Study of TRPV1 in the Lower Urinary Tract: Clinical Relevance and Potential for Innovation

Capsaicin acts on sensory nerves via vanilloid receptors. TRPV1 has been extensively studied with respect to functional lower urinary tract (LUT) conditions in rodents and humans. We aimed to (1) provide background information on capsaicin and TRPV1 and its mechanisms of action and basis for clinical use, (2) review the use of acute intravesical capsaicin instillation (AICI) in rodents to mimic various LUT disorders in which capsaicin sensitive C-fibers are involved and (3) discuss future innovative treatments. A comprehensive search of the major literature databases until June 2022 was conducted. Both capsaicin-sensitive and resistant unmyelinated bladder afferent C-fibers are involved in non-neurogenic overactive bladder/detrusor overactivity (OAB/DO). AICI is a suitable model to study afferent hyperactivity mimicking human OAB. Capsaicin-sensitive C-fibers are also involved in neurogenic DO (NDO) and potential targets for NDO treatment. AICI has been successfully tested for NDO treatment in humans. Capsaicin-sensitive bladder afferents are targets for NDO treatment. TRPV1-immunoreactive nerve fibers are involved in the pathogenesis of interstitial cystitis/painful bladder syndrome (IC/PBS). The AICI experimental model appears relevant for the preclinical study of treatments targeting bladder afferents for refractory IC/BPS. The activity of capsaicin-sensitive bladder afferents is increased in experimental bladder outlet obstruction (BOO). The AICI model may also be relevant for bladder disorders resulting from C-fiber hyperexcitabilities related to BOO. In conclusion, there is a rationale for the selective blockade of TRPV1 channels for various bladder disorders. The AICI model is clinically relevant for the investigation of pathophysiological conditions in which bladder C-fiber afferents are overexcited and for assessing innovative treatments for bladder disorders based on their pathophysiology.

Comparative effectiveness and safety of intravesical instillation treatment of interstitial cystitis/bladder pain syndrome: a systematic review and network meta-analysis of randomized controlled trials

INTRODUCTION AND HYPOTHESIS

A large variety of agents are available for intravesical instillation treatment of interstitial cystitis/bladder pain syndrome (IC/BPS). The purpose of the study was to compare the efficacy and safety of those agents.

METHODS

PubMed, the Cochrane Library, and Embase were searched from database inception to February 2020 for randomized controlled trials. The language of publication was limited in English. Population, intervention, comparison, outcome, and study design was used to assess the eligible studies for inclusion and the Cochrane Collaboration's risk of bias tool was used to assess the methodological quality of the studies included. The primary outcome was O'Leary-Sant Interstitial Cystitis Problem Index (ICPI) and O'Leary-Sant Interstitial Cystitis Symptom Index (ICSI) improvement.

RESULTS

Eleven randomized controlled trials covering 8 agents with 902 patients were enrolled. According to the results of the ICPI and ICSI, 0.1 μM resiniferatoxin was more effective than other therapies. Combination therapy of hyaluronic acid and chondroitin sulphate ranked second in ICSI, third in ICPI, and first in the visual analog scale (VAS). Among regimens included for complication comparison, chondroitin sulphate was safer than other agents, with a probability of 78.5%.

CONCLUSIONS

Resiniferatoxin (0.1 μM) is more effective at ICPI and ICSI improvement than other agents. More well-designed randomized controlled trials with a large sample size directly comparing the efficacy and safety of those agents are in need in the future to confirm our findings.

Interventions for treating people with symptoms of bladder pain syndrome: a network meta-analysis

BACKGROUND

Bladder pain syndrome (BPS), which includes the condition of interstitial cystitis, is a poorly understood clinical condition for which patients present with varying symptoms. Management of BPS is challenging for both patients and practitioners. At present, there is no universally accepted diagnosis and diverse causes have been proposed. This is reflected in wide-ranging treatment options, used alone or in combination, with limited evidence. A network meta-analysis (NMA) simultaneously comparing multiple treatments may help to determine the best treatment options for patients with BPS.

OBJECTIVES

To conduct a network meta-analysis to assess the effects of interventions for treating people with symptoms of bladder pain syndrome (BPS).

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL, in the Cochrane Library), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and handsearched journals and conference proceedings (searched 11 May 2018) and the reference lists of relevant articles. We conducted a further search on 5 June 2019, which yielded four small studies that were screened for eligibility but were not incorporated into the review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of interventions for treating adults with BPS. All types of interventions (including conservative, pharmacological and surgical) were eligible.

DATA COLLECTION AND ANALYSIS

We assessed the risk of bias of included studies using Cochrane's 'Risk of bias' tool. Primary outcomes were the number of people cured or improved, pain, frequency and nocturia. For each outcome, random-effects NMA models were fitted using WinBUGS 1.4. We monitored median odds ratios (ORs) for binary outcomes and mean differences (MDs) for continuous outcomes with 95% credible intervals (Crls). We compared results of the NMA with direct evidence from pairwise meta-analysis of head-to-head trials. We used the CINeMA tool to assess the certainty of evidence for selected treatment categories.

MAIN RESULTS

We included 81 RCTs involving 4674 people with a median of 38 participants (range 10 to 369) per RCT. Most trials compared treatment against control; few trials compared two active treatments. There were 65 different active treatments, and some comparisons were informed by direct evidence from only one trial. To simplify, treatments were grouped into 31 treatment categories by mode of action. Most studies were judged to have unclear or high risk of bias for most domains, particularly for selection and detection bias. Overall, the NMA suggested that six (proportion cured/improved), one (pain), one (frequency) and zero (nocturia) treatment categories were effective compared with control, but there was great uncertainty around estimates of effect. Due to the large number of intervention comparisons in this review, we focus on three interventions: antidepressants, pentosan polysulfate (PPS) and neuromuscular blockade. We selected these interventions on the basis that they are given 'strong recommendations' in the EAU Guidelines for management of BPS (EAU Guidelines 2019). We found very low-certainty evidence suggesting that antidepressants were associated with greater likelihood of cure or improvement compared with control (OR 5.91, 95% CrI 1.12 to 37.56), but it was uncertain whether they reduced pain (MD -1.27, 95% CrI -3.25 to 0.71; low-certainty evidence), daytime frequency (MD -2.41, 95% CrI -6.85 to 2.05; very low-certainty evidence) or nocturia (MD 0.01, 95% CrI -2.53 to 2.50; very low-certainty evidence). There was no evidence that PPS had improved cure/improvement rates (OR 0.14, 95% CrI 0.40 to 3.35; very low-certainty evidence) or reduced pain (MD 0.42, 95% CrI -1.04 to 1.91; low-certainty evidence), frequency (MD -0.37, 95% CrI -5.00 to 3.44; very low-certainty evidence) or nocturia (MD -1.20, 95% CrI -3.62 to 1.28; very low-certainty evidence). There was evidence that neuromuscular blockade resulted in greater cure or improvement (OR 5.80, 95% CrI 2.08 to 18.30) but no evidence that it improved pain (MD -0.33, 95% CrI -1.71 to 1.03), frequency (MD -0.91, 95% CrI -3.24, 1.29) or nocturia (MD -0.04, 95% CrI -1.35 to 1.27). The certainty of this evidence was always very low.

AUTHORS' CONCLUSIONS

We are uncertain whether some treatments may be effective in treating patients with BPS because the certainty of evidence was generally low or very low. Data were available for a relatively large number of trials, but most had small sample sizes and effects of treatments often could not be estimated with precision. An NMA was successfully conducted, but limited numbers of small trials for each treatment category hampered our ability to fully exploit the advantages of this analysis. Larger, more focused trials are needed to improve the current evidence base.

Regulation of transient receptor potential cation channel subfamily V1 protein synthesis by the phosphoinositide 3-kinase/Akt pathway in colonic hypersensitivity

The transient receptor potential cation channel subfamily V member 1 (TRPV1), also known as the capsaicin receptor or vanilloid receptor 1 (VR1), is expressed in nociceptive neurons in the dorsal root ganglia (DRG) and participates in the transmission of pain. The present study investigated the underlying molecular mechanisms by which TRPV1 was regulated by nerve growth factor (NGF) signaling pathways in colonic hypersensitivity in response to colitis. We found that during colitis TRPV1 protein levels were significantly increased in specifically labeled colonic afferent neurons in both L1 and S1 DRGs. TRPV1 protein up-regulation in DRG was also enhanced by NGF treatment. We then found that TRPV1 protein up-regulation in DRG was regulated by activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway both in vivo and in vitro. Suppression of endogenous PI3K/Akt activity during colitis or NGF treatment with a specific PI3K inhibitor LY294002 reduced TRPV1 protein production in DRG neurons, and also reduced colitis-evoked TRPV1-mediated visceral hypersensitivity tested by hyper-responsiveness to colorectal distention (CRD) and von Frey filament stimulation of abdomen. Further studies showed that TRPV1 mRNA levels in the DRG were not regulated by either colitis or NGF. We then found that an up-regulation of the protein synthesis pathway was involved by which both colitis and NGF caused a PI3K-dependent increase in the phosphorylation level of eukaryotic translation initiation factor 4E-binding protein (4E-BP)1. These results suggest a novel mechanism in colonic hypersensitivity which involves PI3K/Akt-mediated TRPV1 protein, not mRNA, up-regulation in primary afferent neurons, likely through activation of the protein synthesis pathways.

Intravesical treatment for interstitial cystitis/painful bladder syndrome: a network meta-analysis

INTRODUCTION AND HYPOTHESIS

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic inflammatory condition of the submucosal and muscular layers of the bladder. So far, there is no effective and targeted treatment strategy for IC/PBS. This study aimed to assess the efficacy and safety of intravesical instillation treatment in IC/PBS patients.

METHODS

We searched various databases up to October 2015. A network meta-analysis was performed to compare global response assessment (GRA) for different treatment strategies, including botulinum toxin A (BoNTA), bacillus Calmette-Guerin (BCG), resiniferatoxin (RTX), lidocaine, chondroitin sulfate (CS), oxybutynin, and pentosan polysulfate (PPS). A traditional meta-analysis was also performed.

RESULTS

Sixteen trials evaluating 905 patients were included. Network meta-analysis indicated that BoNTA had the highest probability of being the best treatment course according to GRA assessment results (probability 81.7 %). BCG or BoNTA therapy yielded significant improvement in GRA incidence according to traditional meta-analysis. Patients who received PPS showed higher urinary frequency results compared with the placebo groups. BCG- and PPS-treated patients had elevated urinary urgency treatment effects compared with placebo groups. Bladder capacity restoration results also showed significant improvements in patients who received BoNTA compared with placebo-treated individuals.

CONCLUSIONS

These findings indicate that BoNTA therapy has the highest probability of being the best therapy according to GRA, and significantly improves bladder capacity in IC/PBS patients. BCG treatment also significantly increases the incidence of GRA and improves the symptoms of urinary urgency. PPS can significantly improve urinary frequency and urgency symptoms in IC/PBS patients.

Review of intravesical therapies for bladder pain syndrome/interstitial cystitis

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a chronic pain condition characterised by urinary frequency, urgency and pain or discomfort which the patient attributes to the bladder. It is a complex condition to manage and treat and requires a multi-disciplinary and multi-modal approach. As well as lifestyle and behavioural modifications, physical therapy and oral medications, intravesical treatments can be used in the treatment algorithm for BPS/IC. A number of intravesical agents are reviewed in this paper along with the available evidence for their use.

Use of vanilloids in urologic disorders

The bladder is an organ rich in vanilloid targets: dense unmyelinated c-fibers partially responsible for bladder sensation and response to noxious stimuli. Drugs such as capsaicin and resiniferatoxin (RTX) interact with the VR1 vanilloid receptor subtype to initially excite then subsequently desensitize the c-fibers. This chapter examines the literature describing the use of vanilloid receptor agonists in the treatment of the following urological disorders: neurogenic bladder (NGB), overactive bladder (OAB), and interstitial cystitis/painful bladder syndrome (IC/PBS). Review of the literature was performed using Pubmed and the following key words "capsaicin," "resiniferatoxin (RTX)," and "neurogenic bladder," "overactive bladder (OAB)," and "interstitial cystitis," "painful bladder syndrome." Articles focusing on randomized trials comparing intravesical administration of a vanilloid receptor agonist to placebo and those in English were reviewed. We conclude that capsaicin and RTX do appear to provide some acceptable treatment results in patients with neurogenic bladder, though larger studies are needed to confirm this. Although efficacy has been shown in some studies, currently the use of vanilloids cannot be recommended for routine use in patients with OAB as the need for catheterization may cause the risk to outweigh the benefit of treatment. Similarly, for the treatment of BPS, vanilloid receptor agonists lack strong evidence for efficacy or tolerability; larger studies are needed to define their role. Understanding how vanilloids are able to impact these disorders, however, may help further elucidate their underlying pathophysiological processes.

Variations in the reporting of outcomes used in systematic reviews of treatment effectiveness research in bladder pain syndrome

This paper investigates the quality of outcomes reported in systematic reviews and randomised controlled trials (RCTs) of bladder pain syndrome and its relationship with study quality and journal impact factor. We searched until August 2013 the Cochrane Library, EMBASE, Medline, CINAHL, LILACS and SIGLE, without language restrictions. Quality of outcome reporting in systematic reviews and constituent RCTs was assessed using a 6-point scale. Overall study quality was assessed using the AMSTAR and Jadad scoring systems, and impact factor in the year of publication was noted. Spearman's rank correlation was calculated. There were 8 systematic reviews, with a total of 28 RCTs (1732 patients), reporting 5 outcomes using 19 different measurement scales. The outcomes reported in individual RCTs were urinary symptoms (100%), pain (64%), quality of life (39%), general wellbeing (36%) and bladder capacity (36%). The mean quality of outcomes reported was 1.63 (95% CI 0.29-2.96) for systematic reviews and 3.25 (95% CI 2.80-3.70) for RCTs. The quality of outcomes reported showed correlation with overall study quality (0.90, 95% CI 0.79-0.95, p<0.0001) but not with journal impact factor (0.07, 95% CI -0.31-0.43, p=0.35). Multivariable linear regression showed a relationship between quality of outcome reporting and study quality (β=0.05, p<0.0001), adjusting for effects of study type, impact factor and journal type. There is a need to generate consensus over a set of core outcomes in bladder pain syndrome using standardised reporting tools and to disseminate these through good publication practice.

Current recommendations for bladder instillation therapy in the treatment of interstitial cystitis/bladder pain syndrome

Bladder instillation therapy refers to the direct introduction of medication into the bladder and is a common treatment modality for patients with interstitial cystitis/bladder pain syndrome (IC/BPS) who have failed conservative and oral therapies. The current American Urological Association (AUA) recommendations list three medications as options for IC/BPS instillation therapy: dimethyl sulfoxide, heparin, and lidocaine. The purpose of this review is to examine the evidence behind the recommendations for these medications. We also examine several historical or experimental therapies that do not hold recommendations but are still used on rare occasion. Finally, we discuss our bladder instillation strategies as well as potential future research and development in intravesicular therapy.

Intravesical resiniferatoxin for the treatment of storage lower urinary tract symptoms in patients with either interstitial cystitis or detrusor overactivity: a meta-analysis

Background

While Resin­iferatoxin (RTX) has been widely used for patients with storage lower urinary tract symptoms (LUTS), its clinical efficiency hasn't yet been well evaluated. A meta-analysis was performed to evaluate the exact roles of intravesical RTX for the treatment of storage LUTS in patients with either interstitial cystitis (IC) or detrusor overactivity (DO).

Methods

A meta-analysis of RTX treatment was performed through a comprehensive search of the literature. In total, 2,332 records were initially recruited, 1,907 from Elsevier, 207 from Medline and 218 from the Web of Science. No records were retrieved from the Embase or Cochrane Library. Seven trials with 355 patients were included and one trial was excluded because of the lack of extractable data. The analyses were all performed using RevMan 5.1 and MIX 2.0.

Results

Bladder pain was significantly reduced after RTX therapy in patients with either IC or DO. The average decrease of the visual an alogue pain scale was 0.42 after RTX treatment (p = 0.02). The maximum cystometric capacity (MCC) was significantly increased in patients with DO (MCC increase, 53.36 ml, p = 0.006) but not in those with IC (MCC increase, −19.1 ml, p = 0.35). No significant improvement in urinary frequency, nocturia, incontinence or the first involuntary detrusor contraction (FDC) was noted after RTX therapy (p = 0.06, p = 0.52, p = 0.19 and p = 0.41, respectively).

Conclusions

RTX could significantly reduce bladder pain in patients with either IC or DO, and increase MCC in patients with DO; however, no significant improvement was observed in frequency, nocturia, incontinence or FDC. Given the limitations in the small patient size and risk of bias in the included trials, great caution should be taken when intravesical RTX is used before a large, multicenter, well-designed random control trial with a long-term follow-up is carried out to further assess the clinical efficacy of RTX in in patients with storage LUTS.

Resiniferatoxin for Pain Treatment: An Interventional Approach to Personalized Pain Medicine

This review examines existing preclinical and clinical studies related to resiniferatoxin (RTX) and its potential uses in pain treatment. Like capsaicin, RTX is a vanilloid receptor (TRPV1) agonist, only more potent. This increased potency confers both quantitative and qualitative advantages in terms of drug action on the TRPV1 containing nerve terminal, which result in an increased efficacy and a long duration of action. RTX can be delivered by a central route of administration through injection into the subarachnoid space around the lumbosacral spinal cord. It can also be administered peripherally into a region of skin or deep tissue where primary afferents nerves terminate, or directly into a nerve trunk or a dorsal root ganglion. The central route is currently being evaluated as a treatment for intractable pain in patients with advanced cancer. Peripheral administration offers the possibility to treat a wide diversity of pain problems because of the ability to bring the treatment to the site of the pain (the peripheral generator). While not all pain disorders are appropriate for RTX, tailoring treatment to an individual patient's needs via a selective and local intervention that chemically targets a specific population of nerve terminals provides a new capability for pain therapy and a simplified and effective approach to personalized pain medicine.

Lack of transient receptor potential vanilloid 1 channel modulates the development of neurogenic bladder dysfunction induced by cross-sensitization in afferent pathways

Background

Bladder pain of unknown etiology has been associated with co-morbid conditions and functional abnormalities in neighboring pelvic organs. Mechanisms underlying pain co-morbidities include cross-sensitization, which occurs predominantly via convergent neural pathways connecting distinct pelvic organs. Our previous results showed that colonic inflammation caused detrusor instability via activation of transient receptor potential vanilloid 1 (TRPV1) signaling pathways, therefore, we aimed to determine whether neurogenic bladder dysfunction can develop in the absence of TRPV1 receptors.

Methods

Adult male C57BL/6 wild-type (WT) and TRPV1^−/− (knockout) mice were used in this study. Colonic inflammation was induced by intracolonic trinitrobenzene sulfonic acid (TNBS). The effects of transient colitis on abdominal sensitivity and function of the urinary bladder were evaluated by cystometry, contractility and relaxation of detrusor smooth muscle (DSM) in vitro to various stimuli, gene and protein expression of voltage-gated sodium channels in bladder sensory neurons, and pelvic responses to mechanical stimulation.

Results

Knockout of TRPV1 gene did not eliminate the development of cross-sensitization between the colon and urinary bladder. However, TRPV1^−/− mice had prolonged intermicturition interval and increased number of non-voiding contractions at baseline followed by reduced urodynamic responses during active colitis. Contractility of DSM was up-regulated in response to KCl in TRPV1^−/− mice with inflamed colon. Application of Rho-kinase inhibitor caused relaxation of DSM in WT but not in TRPV1^−/− mice during colonic inflammation. TRPV1^−/− mice demonstrated blunted effects of TNBS-induced colitis on expression and function of voltage-gated sodium channels in bladder sensory neurons, and delayed development of abdominal hypersensitivity upon colon-bladder cross-talk in genetically modified animals.

Conclusions

The lack of TRPV1 receptors does not eliminate the development of cross-sensitization in the pelvis. However, the function of the urinary bladder significantly differs between WT and TRPV^−/− mice especially upon development of colon-bladder cross-sensitization induced by transient colitis. Our results suggest that TRPV1 pathways may participate in the development of chronic pelvic pain co-morbidities in humans.

Differential effects of intravesical resiniferatoxin on excitability of bladder spinal neurons upon colon-bladder cross-sensitization

Cross-sensitization in the pelvis may contribute to etiology of functional pelvic pain disorders such as interstitial cystitis/bladder pain syndrome (IC/BPS). Increasing evidence suggests the involvement of transient receptor potential vanilloid 1 (TRPV1) receptors in the development of neurogenic inflammation in the pelvis and pelvic organ cross-sensitization. The objective of this study was to test the hypothesis that desensitization of TRPV1 receptors in the urinary bladder can minimize the effects of cross-sensitization induced by experimental colitis on excitability of bladder spinal neurons. Extracellular activity of bladder neurons was recorded in response to graded urinary bladder distension (UBD) in rats pretreated with intravesical resiniferatoxin (RTX, 10(-7)M). Colonic inflammation was induced by intracolonic instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS). The duration of excitatory responses to noxious UBD during acute colonic inflammation (3 days post-TNBS) was significantly shortened in the group with RTX pretreatment (25.3±1.5s, n=49) when compared to the control group (35.1±4.2s, n=43, p<0.05). The duration of long-lasting excitatory responses, but not short-lasting responses of bladder spinal neurons during acute colitis was significantly reduced by RTX from 52.9±6.6s (n=21, vehicle group) to 34.4±2.1s (RTX group, n=21, p<0.05). However, activation of TRPV1 receptors in the urinary bladder prior to acute colitis increased the number of bladder neurons receiving input from large somatic fields from 22.7% to 58.2% (p<0.01). The results of our study provide evidence that intravesical RTX reduces the effects of viscerovisceral cross-talk induced by colonic inflammation on bladder spinal neurons. However, RTX enhances the responses of bladder neurons to somatic stimulation, thereby limiting its therapeutic potential.

Diagnosis and treatment of interstitial cystitis in adolescents

Interstitial cystitis (IC), or painful bladder syndrome, is characterized by irritative voiding symptoms and can be a challenging problem that affects children and adolescents. Diagnosis and management in children and adolescents is challenging because of strict diagnostic criteria and the paucity of investigations focusing on this age group, which often can lead to delayed or missed diagnosis. Clinical features suggestive of IC include bladder pain, urgency, frequency, nocturia, and pressure. Symptoms may wax and wane and often are exacerbated by menstruation, intercourse, dietary triggers, and stress. Diagnosis can be made by history, physical exam findings such as suprapubic tenderness, voiding diaries, and exclusion of other etiologies. Some diagnostic tests such as the potassium sensitivity test and cystoscopy are invasive and often impractical in younger patients. Treatment of IC consists of a multimodal approach that should be tailored to the individual needs of the patient. Therapies for younger patients include oral medication, intravesical therapy, cystoscopy with hydrodistention, and conservative measures such as dietary modification. This review of the literature focuses on diagnosing IC in younger patients and on what treatment modalities are appropriate and effective for this age group.

Effects of combination treatment of intravesical resiniferatoxin instillation and hydrodistention in patients with refractory painful bladder syndrome/interstitial cystitis: a pilot study

PURPOSE

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a disabling disease of the urinary bladder, and its etiology and treatment are not yet established. Current medications used in the treatment of PBS/IC have shown limited efficacy. This prospective study investigated the efficacy of intravesical resiniferatoxin (RTX) in PBS/IC refractory to medical treatment.

METHODS

Patients with proven PBS/IC refractory to traditional medical treatment were enrolled. By randomized trial, a total of 18 consecutive patients were divided into two groups: treatment with hydrodistention and intravesical RTX (group 1) or treatment with hydrodistension only (group 2). We assessed bladder pain by use of a visual analogue pain scale, the maximal urine flow rate, post-void residual urine volume, and a voiding diary before and 3 months after treatment.

RESULTS

The median age of the 18 patients was 55.8±6.9 years, and the median duration of symptoms before diagnosis was 3.6±1.6 years. Frequency, functional bladder capacity, and score on a 5-point pain scale were significantly improved at 3-month after treatment in both groups. Intravesical RTX instillation plus hydrodistention, compared with hydrodistention only, did not have a significant effect on the voiding symptoms or uroflowmetry of the patients but significantly improved scores on the pain scale.

CONCLUSIONS

Intravesical RTX instillation plus hydrodistention was effective in relieving pain but was not effective in improving lower urinary tract symptoms. Further larger studies are needed to clarify the efficacy of combination treatment of intravesical RTX instillation and hydrodistention.

Up-regulation of brain-derived neurotrophic factor in primary afferent pathway regulates colon-to-bladder cross-sensitization in rat

Background

In humans, inflammation of either the urinary bladder or the distal colon often results in sensory cross-sensitization between these organs. Limited information is known about the mechanisms underlying this clinical syndrome. Studies with animal models have demonstrated that activation of primary afferent pathways may have a role in mediating viscero-visceral cross-organ sensitization.

Methods

Colonic inflammation was induced by a single dose of tri-nitrobenzene sulfonic acid (TNBS) instilled intracolonically. The histology of the colon and the urinary bladder was examined by hematoxylin and eosin (H&E) stain. The protein expression of transient receptor potential (TRP) ion channel of the vanilloid type 1 (TRPV1) and brain-derived neurotrophic factor (BDNF) were examined by immunohistochemistry and/or western blot. The inter-micturition intervals and the quantity of urine voided were obtained from analysis of cystometrograms.

Results

At 3 days post TNBS treatment, the protein level of TRPV1 was increased by 2-fold (p < 0.05) in the inflamed distal colon when examined with western blot. TRPV1 was mainly expressed in the axonal terminals in submucosal area of the distal colon, and was co-localized with the neural marker PGP9.5. In sensory neurons in the dorsal root ganglia (DRG), BDNF expression was augmented by colonic inflammation examined in the L1 DRG, and was expressed in TRPV1 positive neurons. The elevated level of BDNF in L1 DRG by colonic inflammation was blunted by prolonged pre-treatment of the animals with the neurotoxin resiniferatoxin (RTX). Colonic inflammation did not alter either the morphology of the urinary bladder or the expression level of TRPV1 in this viscus. However, colonic inflammation decreased the inter-micturition intervals and decreased the quantities of urine voided. The increased bladder activity by colonic inflammation was attenuated by prolonged intraluminal treatment with RTX or treatment with intrathecal BDNF neutralizing antibody.

Conclusion

Acute colonic inflammation increases bladder activity without affecting bladder morphology. Primary afferent-mediated BDNF up-regulation in the sensory neurons regulates, at least in part, the bladder activity during colonic inflammation.

Interstitial cystitis: diagnosis and management

Interstitial cystitis/painful bladder syndrome is a chronic condition that causes debilitating bladder pain which can be associated with urgency, frequency and nocturia. Its cause is not clear and it is still a disease diagnosed by exclusion. Oral or intravesical therapies are the main stay of treatment whilst surgical procedures are reserved for refractory cases. This condition usually warrants a multidisciplinary approach for optimum outcome. This article gives an overview of the changes in definition, aetiopathogenesis and available treatments.

Contemporary management of the painful bladder: a systematic review

CONTEXT

Different types of behavioural, dietary, interventional, pharmacologic, and surgical therapies have been used to treat painful bladder syndrome/interstitial cystitis (PBS/IC). Because of the paucity of randomised placebo-controlled studies on different treatments, an evidence-based management approach has not yet been developed.

OBJECTIVE

To critically review and synthesize data from a wide range of current therapeutic approaches to PBS/IC, to quantify the effect size from randomised controlled trials (RCTs), and to reach clinical agreement on the efficacy of treatments for PBS/IC.

EVIDENCE ACQUISITION

We performed a systematic review of the literature to identify articles published between 1990 and September 2010 on the management of PBS/IC. We included articles restricted to the English language published since 1990 to date that reported on oral and intravesical treatment, multimodal or combined treatment, and surgical treatment. For all RCTs, standardised mean differences (SMDs) were extracted and combined in a meta-analysis applying a random-effect model that incorporated the heterogeneity of effects. The four outcomes assessed in all studies were a change in the Interstitial Cystitis Symptom Index (ICSI), pain, urgency, and frequency. Non-RCTs (nRCTs) were analysed with a narrative synthesis of the evidence from all research designs.

EVIDENCE SYNTHESIS

We included 7709 adult patients from 29 RCTs and 57 nRCTs. Meta-analysis of RCTs showed that only cyclosporine A provided a simultaneous great effect size of SMD on ICSI, pain, and frequency. Amitriptyline at different dosages showed a great effect size of SMD on pain and urgency or on ICSI and frequency. The remaining RCTs showed sporadic significant changes in only one of the four considered parameters. The attributed levels of evidence for treatments reported in RCTs were 1b; grades of recommendations ranged from A to C. According to the Jadad score, 11 RCTs were high-quality studies. Meta-analysis of RCTs showed a great heterogeneity in the applied methodologies, clinical outcomes assessed, and the obtained results in different studies. The results from the nRCTs showed that the most frequently adopted treatment is oral pentosan polysulfate and that the use of botulinum A toxin intradetrusorial injections in PBS/IC is increasing. A high heterogeneity in drugs and treatment modalities, clinical outcomes, and obtained results was also found for nRCTs.

CONCLUSIONS

Limited evidence exists for the few treatments for PBS/IC. The lack of definitive conclusions is due to the great heterogeneity in methodology, symptoms assessment, duration of treatment, and follow-up in both RCTs and nRCTs.

Acute colonic inflammation triggers detrusor instability via activation of TRPV1 receptors in a rat model of pelvic organ cross-sensitization

Chronic pelvic pain of unknown etiology is a common clinical condition and may develop as a result of cross-sensitization in the pelvis when pathological changes in one of the pelvic organs result in functional alterations in an adjacent structure. The aim of the current study was to compare transient receptor potential vanilloid 1 (TRPV1) activated pathways on detrusor contractility in vivo and in vitro using a rat model of pelvic organ cross-sensitization. Four groups of male Sprague-Dawley rats (N = 56) were included in the study. Animals received intracolonic saline (control), resiniferatoxin (RTX, TRPV1 agonist, 10(-7) M), 2,4,6-trinitrobenzene sulfonic acid (TNBS, colonic irritant), or double treatment (RTX followed by TNBS). Detrusor muscle contractility was assessed under in vitro and in vivo conditions. Intracolonic RTX increased the contractility of the isolated detrusor in response to electric field stimulation (EFS) by twofold (P ≤ 0.001) and enhanced the contractile response of the bladder smooth muscle to carbachol (CCh). Acute colonic inflammation reduced detrusor contractility upon application of CCh in vitro, decreased bladder capacity by 28.1% (P ≤ 0.001), and reduced micturition volume by 60% (P ≤ 0.001). These changes were accompanied by an increased number of nonmicturition contractions from 3.7 ± 0.7 to 15 ± 2.7 (N = 6 in both groups, P ≤ 0.001 vs. control). Desensitization of intracolonic TRPV1 receptors before the induction of acute colitis restored the response of isolated detrusor strips to CCh but not to EFS stimulation. Cystometric parameters were significantly improved in animals with double treatment and approximated the control values. Our data suggest that acute colonic inflammation triggers the occurrence of detrusor instability via activation of TRPV1-related pathways. Comparison of the results obtained under in vitro vs. in vivo conditions provides evidence that intact neural pathways are critical for the development of an overactive bladder resulting from pelvic organ cross talk.

AUA guideline for the diagnosis and treatment of interstitial cystitis/bladder pain syndrome

PURPOSE

To provide a clinical framework for the diagnosis and treatment of interstitial cystitis/bladder pain syndrome.

MATERIALS AND METHODS

A systematic review of the literature using the MEDLINE® database (search dates 1/1/83-7/22/09) was conducted to identify peer reviewed publications relevant to the diagnosis and treatment of interstitial cystitis/bladder pain syndrome. Insufficient evidence-based data were retrieved regarding diagnosis and, therefore, this portion of the Guideline is based on Clinical Principles and Expert Opinion statements. The review yielded an evidence base of 86 treatment articles after application of inclusion/exclusion criteria. These publications were used to create the majority of the treatment portion of the Guideline. When sufficient evidence existed, the body of evidence for a particular treatment was assigned a strength rating of A (high), B (moderate) or C (low). Additional treatment information is provided as Clinical Principles and Expert Opinion when insufficient evidence existed. See text and algorithm for definitions, and detailed diagnostic management, and treatment frameworks.

RESULTS

The evidence-based guideline statements are provided for diagnosis and overall management of interstitial cystitis/bladder pain syndrome as well as for various treatments. The panel identified first through sixth line treatments as well as developed guideline statements on treatments that should not be offered.

CONCLUSIONS

Interstitial cystitis/bladder pain syndrome is best identified and managed through use of a logical algorithm such as is presented in this Guideline. In the algorithm the panel identifies an overall management strategy for the interstitial cystitis/bladder pain syndrome patient. Diagnosis and treatment methodologies can be expected to change as the evidence base grows in the future.

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A

The persisting interest around neurotoxins such as vanilloids and botulinum toxin (BoNT) derives from their marked effect on detrusor overactivity refractory to conventional antimuscarinic treatments. In addition, both are administered by intravesical route. This offers three potential advantages. First, intravesical therapy is an easy way to provide high concentrations of pharmacological agents in the bladder tissue without causing unsuitable levels in other organs. Second, drugs effective on the bladder, but inappropriate for systemic administration, can be safely used as it is the case of vanilloids and BoNT. Third, the effects of one single treatment might be extremely longlasting, contributing to render these therapies highly attractive to patients despite the fact that the reasons to the prolonged effect are still incompletely understood. Attractive as it may be, intravesical pharmacological therapy should still be considered as a second-line treatment in patients refractory to conventional oral antimuscarinic therapy or who do not tolerate its systemic side effects. However, the increasing off-label use of these neurotoxins justifies a reappraisal of their pharmacological properties.

[Specific treatments for painful bladder syndrome]

INTRODUCTION

Painful bladder syndrome is defined as chronic pelvic pain present for more than 6 months, causing discomfort perceived as being related to the bladder and accompanied by a persistent and strong urge to urinate or urinary frequency. The purpose of this article is to review the treatment of painful bladder syndrome.

MATERIAL AND METHODS

A comprehensive review of the literature was performed by searching PUBMED for articles on specific treatments for painful bladder syndrome.

RESULTS

Many treatments have been proposed for the management of painful bladder syndrome: local intravesical treatments (glucosaminoglycan [pentosan polysulfate], dimethylsulfoxide [DMSO], heparin, bacillus Calmette-Guérin [BCG], anticholinergic agents [oxybutynin, etc.] or oral treatments [glucosaminoglycan (pentosan polysulfate), antihistamines, antidepressants, immunosuppressives, etc.]) with an action on the pathophysiology of this syndrome. The efficacy of these various treatments has been limited, with trials based on small numbers of patients and not always conducted according to a randomized, prospective design. Other salvage treatments (neuromodulation, botulinum toxin, surgery, etc.) have also been reported with limited efficacy, but allowing salvage of treatment failures.

CONCLUSION

The therapeutic management of painful bladder syndrome is complex. The large number of proposed treatment modalities present a limited efficacy with discordant results from one study to another making comparisons and analyses difficult.

Experimental colitis triggers the release of substance P and calcitonin gene-related peptide in the urinary bladder via TRPV1 signaling pathways

Clinical data provide evidence of high level of co-morbidity among genitourinary and gastrointestinal disorders characterized by chronic pelvic pain. The objective of this study was to test the hypothesis that colonic inflammation can impact the function of the urinary bladder via activation of TRPV1 signaling pathways followed by alterations in gene and protein expression of substance P (SP) and calcitonin gene-related peptide (CGRP) in sensory neurons and in the bladder. Inflammation was induced by intracolonic instillation of trinitrobenzene sulfonic acid (TNBS, 12.5mg/kg), and desensitization of TRPV1 receptors was evoked by intracolonic resiniferatoxin (RTX, 10(-)(7)M). mRNA and protein concentrations of CGRP and SP were measured at 3, 5 and 30 days. RTX instillation in the colon caused 3-fold up-regulation of SP mRNA in the urinary bladder at day 5 (n=7, p ≤ 0.05) followed by 35-fold increase at day 30 (n=5, p ≤ 0.05). Likewise, TNBS colitis triggered 15.8-fold up-regulation of SP mRNA 1 month after TNBS (n=5, p ≤ 0.05). Desensitization of colonic TRPV1 receptors prior to TNBS abolished SP increase in the urinary bladder. RTX led to 4.3-fold increase of CGRP mRNA at day 5 (n=7, p ≤ 0.05 to control) in the bladder followed by 28-fold increase at day 30 post-RTX (n=4, p ≤ 0.05). Colitis did not alter CGRP concentration during acute phase; however, at day 30 mRNA level was increased by 17.8 ± 6.9-fold (n=5, p ≤ 0.05) in parallel with 4-fold increase in CGRP protein (n=5, p ≤ 0.01) in the detrusor. Protein concentration of CGRP in the spinal cord was diminished by 45-65% (p ≤ 0.05) during colitis. RTX pretreatment did not affect CGRP concentration in the urinary bladder; however, it caused a reduction in CGRP release from lumbosacral DRG neurons during acute phase (3 and 5 days post-TNBS). Our results clearly demonstrate that colonic inflammation triggers the release of pro-inflammatory neuropeptides SP and CGRP in the urinary bladder via activation of TRPV1 signaling mechanisms enunciating the neurogenic nature of pelvic organ cross-sensitization.

Genitourinary pain syndromes, prostatitis, and lower urinary tract symptoms

The overlap of pain and urinary voiding symptoms is common for urologic patients. The etiology of these syndromes is frequently multifactorial and due to disorders of the bladder and/or prostate. The evaluation and treatment of these syndromes continues to evolve. Here we summarize the general approach to evaluation and treatment of these pain syndromes.

Interstitial cystitis: an unsolved enigma

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a chronic disease of unknown etiology characterized by vague bladder pain and nonspecific urinary symptoms, such as urgency and frequency. Although it was initially considered to be a rare condition, its prevalence has significantly increased, possibly because of different definitions used and greater physician awareness. Because of the multiple diagnostic criteria used, there is significant variation in its prevalence. In addition, there is often a delay in the diagnosis of PBS/IC. It affects predominantly women of middle age, and it significantly decreases quality of life. Diagnosis of PBS/IC is mainly a diagnosis of exclusion; there are no characteristic symptoms or pathognomonic findings. Therefore, it is important to rule out diseases that have a similar clinical picture (i.e., urinary infections, bladder carcinoma) but definite therapies and worse prognosis if left untreated. PBS/IC management suffers from lack of evidence; many therapies are empiric or based on small studies and case series. Treatment includes supportive therapies (psychosocial, behavioral, physical), oral treatments, and intravesical treatments, whereas other more invasive treatments such as electric neuromodulation and reconstructive surgery are reserved for refractory cases. Physicians should always keep in mind the diagnosis of PBS/IC in patients presenting with chronic urinary symptoms after excluding other more common diseases.

Pharmacologic management of painful bladder syndrome/interstitial cystitis: a systematic review

BACKGROUND

More than 180 different types of therapy have been used in the treatment and management of painful bladder syndrome/interstitial cystitis (PBS/IC), yet evidence from clinical trials remains inconclusive. This study aimed to evaluate the efficacy of pharmacologic approaches to PBS/IC, to quantify the effect size from randomized controlled trials, and to begin to inform a clinical consensus of treatment efficacy for PBS/IC.

METHODS

We identified randomized controlled trials for the pharmacologic treatment of patients with PBS/IC diagnosed on the basis of National Institute of Diabetes and Digestive and Kidney Diseases or operational criteria. Study limitations include considerable patient heterogeneity as well as variability in the definition of symptoms and in outcome assessment.

RESULTS

We included a total of 1470 adult patients from 21 randomized controlled trials. Only trials for pentosan polysulfate sodium had sufficient numbers to allow a pooled analysis of effect. According to a random-effects model, the pooled estimate of the effect of pentosan polysulfate therapy suggested benefit, with a relative risk of 1.78 for patient-reported improvement in symptoms (95% confidence interval, 1.34-2.35). This result was not heterogeneous (P = .47) and was without evidence of publication bias (P = .18). Current evidence also suggests the efficacy of dimethyl sulfoxide and amitryptyline therapy. Hydroxyzine, intravesical bacille Calmette-Guérin, and resiniferatoxin therapy failed to demonstrate efficacy, but evidence was inconclusive owing to methodological limitations.

CONCLUSIONS

Pentosan polysulfate may be modestly beneficial for symptoms of PBS/IC. There is insufficient evidence for other pharmacologic treatments. A consensus on standardized outcome measures is urgently needed.

Intravesical treatments for painful bladder syndrome/ interstitial cystitis

BACKGROUND

Painful Bladder Syndrome/Interstitial Cystitis (PBS/IC) occurs predominantly in women. It is a poorly-understood condition with symptoms of bladder pain, urinary frequency, urgency and nocturia. Treatments for PBS/IC include dietary/lifestyle interventions, oral medication, intravesical instillations and, in some cases, surgery. Success rates are generally modest and there is little consensus as to the best form of treatment for this condition.

OBJECTIVES

To assess the effectiveness of intravesical treatment for PBS/IC.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group specialised trials register (30 May 2006) as well as reference lists of all selected trials. Recognised researchers in the field were contacted for any additional relevant material.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials were included in the review if they had recruited participants with a clinical diagnosis of PBS/IC and if at least one arm of the trial was treatment with an intravesical preparation. Outcome measures were pre-determined, the primary ones being the effect on pain and bladder capacity. Others included symptomatic response to treatment, quality-of-life assessment, economic factors and adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality, then extracted relevant data from the studies.

MAIN RESULTS

Nine eligible trials were identified - six parallel group, one incomplete cross-over and two cross-over trials - with a total of 616 participants. Six trials compared an 'active' instillation with placebo instillation, two compared different types of instillation, and one was a comparison of an instillation plus bladder training versus bladder training alone. Altogether, the review included trials of six different types of intravesical instillation: Resiniferatoxin, Dimethyl sulfoxide, BCG, pentosanpolysulphate, oxybutin, and alkalinisation of urine pH. Confidence intervals were generally wide. Resiniferatoxin was not associated with sustained differences in the review outcomes reported but pain during instillation and withdrawal from treatment was significantly more common. The data available about Dimethyl sulfoxide (DMSO) were very limited but with no apparent differences from placebo. Groups treated with BCG tended to report less pain and fewer general symptoms. Although adverse events were commonly reported, these were no more common after BCG than after placebo instillation. The few data about Pentosanpolysulphate tended to favour the actively treated, but with wide confidence intervals; there was little information about adverse events. Oxybutinin instillation was associated with increased bladder capacity, reduced frequency, improved quality of life scores and fewer drop-outs. Alkalinisation of urine pH did not make any clear difference, but with potentially wide confidence intervals.

AUTHORS' CONCLUSIONS

Overall, the evidence base for treating PBS/IC using intravesical preparations is limited and the potential for meta-analysis reduced by variation in the outcome measures used. The quality of trial reports was mixed and in some cases this precluded any meaningful data extraction. BCG and oxybutin are reasonably well-tolerated and evidence is most promising for these. Resiniferatoxin showed no evidence of effect for most outcomes and caused pain, which reduced treatment compliance. There is little evidence for the other treatments included in this review. Randomised controlled trials are still needed and study design should incorporate outcomes that are most relevant to these with PBS/IC and should be standardised.

Evaluation of purinergic mechanism for the treatment of voiding dysfunction: a study in conscious spinal cord-injured rats

BACKGROUND

To investigate the effect of a selective P2X(3-)P2X(2/3) purinergic receptor antagonist (a-317491) on detrusor hyperreflexia in conscious chronic spinal cord-injured female rats.

METHODS

Six chronic spinal cord-transected female Sprague-Dawley rats (290-336 g) were used in this study. Spinal transection at the T8-T9 segmental level was performed using aseptic techniques under halothane anesthesia. Fourteen to 16 weeks after spinal transection, A-317491, a selective P2X(3-)P2X(2/3) purinergic receptor antagonist, was administered intravenously in cystometry studies at increasing doses of 0.03, 0.1, 0.3, 1, 3, 10 and 30 micromol/kg at 40-50 minute intervals. Cystometrograms (CMGs) were performed before and after the administration of each dose of the drug.

RESULTS

The continuous filling of CMGs revealed a large number of small-amplitude (> 8 cmH(2)O), non-voiding contractions (NVCs) (average, 9.7 per voiding cycle) preceding voiding contractions (mean amplitude, 31 cmH(2)O; duration, 2.5 minutes), which occurred at an interval of 539 seconds and at a pressure threshold of 5.7 cmH(2)O. When tested in a range of doses (0.03-30 micromol/kg, intravenous), A-317491 in doses between 1 and 30 micromol/kg significantly (p < 0.05) increased the interval between voids by 25%, reduced the number of NVCs by 42-62%, and increased the pressure threshold for voiding by 53-73%, but did not change the amplitude of the duration of the voiding contractions. The effects of the drug were apparent within 10 minutes following administration.

CONCLUSION

These results indicate that purinergic mechanisms, presumably involving P2X(3) or P2X(2/3) receptors on bladder C-fiber afferent nerves, play an important role in the detrusor hyperreflexia that occurs after spinal cord injury in rats.

Rational approaches to the treatment of patients with interstitial cystitis

Symptoms of interstitial cystitis can usually be successfully managed with heparinoid therapy to theoretically alter bladder urothelial abnormalities, and with oral medications to inhibit neural upregulation or to control mast cell dysfunction. Other forms of care ranging from intravesical therapy to endoscopic, percutaneous, or open surgery are options that may be used singly or in combination to optimize symptom reduction.

Multiple Intravesical Instillations of Low-Dose Resiniferatoxin in the Treatment of Refractory Interstitial Cystitis

BACKGROUND

Current medications used in the treatment of interstitial cystitis (IC) have limited efficacy. This prospective study investigated the efficacy of multiple intravesical instillations of resiniferatoxin (RTX) at the concentration of 10 nM.

METHODS

Patients with proven IC previously treated with traditional medications for more than 6 months without clinical benefit were enrolled. They were excluded if bladder outlet obstruction or urinary tract infection was present. Intravesical instillation of low-dose RTX (10 nM) once weekly for 4 weeks was performed at the outpatient department. International Prostate Symptom Score (IPSS), 5-Point Pain Scale, and Quality of Life Index (QOL Index) were recorded. A videourodynamic study was done at baseline and 3 months after treatment.

RESULTS

The therapeutic results and urodynamic parameters were compared between baseline and 3 months. Thirteen patients, including 10 women and 3 men, were enrolled in this study. The mean duration of IC symptoms was 4.4 +/- 2.5 years. The mean duration of active treatment was 15.3 +/- 8.6 months. One female patient dropped out due to severe bladder pain after RTX instillation. Among the 12 patients who completed the study treatment, subjective assessment revealed that 2 had an excellent therapeutic result, 5 had an improved result and 5 remained unchanged from baseline. The overall satisfactory rate was 58.3%. IPSS, 5-Point Pain Scale, and QOL Index were significantly decreased after RTX treatment. There was no significant increase in mean functional bladder capacity or change in urodynamic parameters. No serious adverse event occurred after RTX treatment.

CONCLUSIONS

This study suggests that multiple intravesical instillations of RTX at the concentration of 10 nM are effective in relieving lower urinary tract symptoms in patients with refractory IC. The treatment is tolerable and suitable for use on an outpatient clinic basis.

Sensory bladder disorders

Sensory bladder disorders include disorders involving abnormal sensations resulting from many diseases of the urinary bladder. In a proportion of patients no cause can be found and if pain or pelvic pressure is a part of the symptomatology, they are labelled as having painful bladder syndrome (PBS). In a subgroup of these patients abnormal findings can be demonstrated at cystoscopy and/or by histological examination of bladder biopsies. These patients are categorised as having interstitial cystitis (IC). This paper looks into the differential diagnosis, evaluation and treatment of patients with PBS.

Recent developments of intravesical therapy of painful bladder syndrome/interstitial cystitis: a review

PURPOSE OF REVIEW

Painful bladder syndrome/interstitial cystitis is a chronic sterile inflammatory disease of the bladder of unknown cause. It is characterized by bladder pain, urinary frequency, urgency, and nocturia. Although there are plenty of theories, the cause of the condition remains obscure. An abundance of treatments has been suggested, but very few have been subjected to proper controlled trials. This review focuses on the recently published literature on intravesical therapy strategies in painful bladder syndrome/interstitial cystitis.

RECENT FINDINGS

Bladder irrigation with different agents has been used during years in an attempt to treat painful bladder syndrome/interstitial cystitis. The background for this is the existing theories about urothelial dysfunction. The 'traditional' agent for glycosaminoglycan substitution is hyaluronic acid. Often used are heparin and dimethyl sulfoxide, the actions of which are not quite clear but supposedly on an anti-inflammatory basis. Other agents for intravesical treatment are Bacillus Calmette-Guerin vaccine and botulinum toxin, and some recent studies have pointed to resiniferatoxin and RDP58.

SUMMARY

Painful bladder syndrome/interstitial cystitis persists as a challenging syndrome in urology. Intravesical instillation therapy has basically not changed during the last few years, although some studies have disconfirmed some regimens. Intensive research may hopefully result in more effective treatments in the future.

Advances in the treatment of interstitial cystitis

Recent years have brought dramatic advances in the clinician's ability to offer effective pharmacotherapy to patients who have interstitial cystitis. Medical treatments have been developed and applied to reduce the interstitial cystitis symptoms of pelvic pain and urinary urgency/frequency, and to address underlying causes of the disorder. In addition, advances in the understanding of the natural history of interstitial cystitis have revealed that it is insidiously progressive and the classical definition--rare, severe and difficult to treat--is in fact the relatively uncommon, advanced stage of a disorder that affects most individuals in a mild-to-moderate and readily treatable form. This recognition has led to the identification of large numbers of previously unsuspected cases of interstitial cystitis, and the successful treatment of many individuals in the early stages of interstitial cystitis when it is far more responsive to therapy. A heparinoid-based multimodal medical regimen can effectively control symptoms and address disease pathophysiology in the majority of cases. Intravesical therapeutic solutions are new and promising adjunctive therapies that can offer immediate symptom relief during symptom flares, and for patients who are just beginning medical therapy.